Typically, an emergency lighting system may comprise of an internal backup power. The emergency lighting system may switch to the internal backup power on failure of a main power supply. A user may switch the main power supply off to shut down the emergency lighting system. The emergency lighting system may switch to the internal backup power, if the user switches the main power supply off. Typically, the emergency lighting system may not be able to distinguish between failure of the main power supply and user switching off the main power supply.